We found this circuit in a 1969 Mullard documentation. The same configuration appears elsewhere in this section. The control range is -2 dB to 19.5 dB at 30 Hz.
This circuit triggers the LED when the monitored battery voltage drops below 9 V for 12 V...
We found this circuit in a Radio Electronics from January 1967. The SCR is already the C106, which...
This power source with silicon diodes at a time when valves were still used was found in Radio...